Sacrum Labeling Quiz

1. During a superior-view identification exercise, a pointer marks the projecting anterior margin of the body of S1. What is this landmark?

2. A midline ridge on the posterior sacrum is formed mainly by fused spinous processes. Which structure should be labeled?

3. A disarticulated sacrum is placed with its smoother, concave surface facing the observer. Which surface is visible?

4. A probe passes through one of the anterior sacral foramina. Which neural structures normally emerge through these openings?

5. A student traces the vertebral canal inferiorly from the lumbar spine into the sacrum. What is this continuation called within the sacrum?

6. A label points to the broad superior end of the sacrum that supports the fifth lumbar vertebra. Which region is it?

7. A pointer lies between the median sacral crest and the posterior sacral foramina. Which crest occupies this position and represents fused articular processes?

8. Which description best identifies the dorsal surface of the sacrum?

9. Two small projections flank the sacral hiatus and may connect with the cornua of the coccyx. What are they?

10. In a standard adult sacrum, how many fused sacral vertebrae are typically represented?

11. Four horizontal lines cross the pelvic surface between the paired anterior sacral foramina. What do these lines represent?

12. Which term labels the winglike lateral expansion on either side of the body of S1?

13. Which posterior landmark lies lateral to the posterior sacral foramina and is formed by fused transverse processes?

14. On a posterior specimen, the inferior opening of the sacral canal is exposed because the lowest sacral laminae did not fuse. Which landmark is being identified?

15. A label marks the ear-shaped articular area on the lateral sacrum. With which bone does this surface articulate?

16. On the rough posterior surface, a label identifies one of four paired openings lateral to the sacral crests. What are these openings?